As the scale of Internet becomes larger, various network services spring up one after another, and advanced multimedia systems emerge in endlessly. Because real-time services are sensitive to the features of network, such as transmission delay and time delay jitter, when File Transfer Protocol (FTP) service with a high burst or Hyper Text Transport Protocol (HTTP) service having an image file occurs, the real-time service will be influenced greatly. Moreover, the multimedia service occupies substantial bandwidth, thus the key service to be guaranteed by the network may not be transmitted reliably. Therefore, various Quality of Service (QoS) technologies emerge as required. Internet Engineering Task Force (IETF) has proposed many service models and mechanisms to meet QoS requirements.
Various portal-based applications, services and broadband multimedia services have become important contents of broadband operators, including services provided to common residential users, such as Video/Audio streams, Video On Demand (VOD), Video Multicast, the multimedia interaction, network games requiring a high bandwidth and services provided to commercial users, such as the video conference, the remote education, Virtual Private Network (VPN), Data Private Line with guaranteed QoS, and Internet Protocol Hotel (IPHotel).
The Ethernet technology and the End-To-End Ethernet technology enjoy a high recognition among the Operators and enterprise users. The Ethernet technology has become one of the main technologies for implementing Triple Play and Metropolitan Area Network in the future. Therefore, the Ethernet service may have a cheerful prospect in the future market.
At present, various VPN or Virtual Private Dial-up Network (VPDN) private line solutions, such as V-Switch, Generic Routing Encapsulation (GRE), Layer 2 Tunneling Protocol (L2TP), Multiple Protocols Label Switch (MPLS), have been put forward for these commercial users.
The Intelligent V-Switch (IVS) technology is mainly used for constructing a stable, practical, economic, and carrier-level Metropolitan Area Ethernet. Therefore, telecommunication-level functions with guaranteed QoS and network security protection, such as network maintenance and management, may be implemented. Further, the IVS technology provides core service management capabilities, such as number-based user management, certain mobility, open service and centralized charging management, and the IVS technology also provides services such as intelligent layer 2 flow scheduling, Local Area Network (LAN) private line, and IP flow planning. The occurrence of IVS improve the pure layer-2 capability in current network and plays an important role in the construction of Metropolitan Area Networks in new era.
The V-Switch architecture has a Ethernet VLAN switching and scheduling function, flexible measures for scheduling, setting up and adjusting services, an abundant and extensible layer-2 service provision capability, and Operation, Administration And Maintenance (OAM) tools and information. The logic layers and function model of the V-Switch system are as shown in FIG. 1.
In FIG. 1, the V-Switch system is divided into three layers: V-Switch service control layer, V-Switch connection control layer and V-Switch bearer layer.
The V-Switch connection control layer maintains switching resources in a Data Retransmission Entity (DRE), such as equipment, ports, links and VLAN tags, receives a V-Switch setup request from a Service Control Register (SCR) of the service layer V-Switch, selects a traffic flow path for the V-Switch connection, allocates a bandwidth and Virtual Local Area Network (VLAN) tags, and transmits the control information to the DRE equipment through which the traffic flow passes.
The DRE lies in the V-Switch bearer layer. The DRE forwards the traffic flow in Ethernet frame format according to a VLAN switching table configured by the V-Switch connection control layer.
The contents of the VLAN switching table are as shown in Table 1.
TABLE 1ParameterParameter Descriptionport 1Traffic flow forwarding port 1 , such as GE 1/0/0vlan id 1VLAN ID carried in traffic flow on Port 1 in theEthernet frame formatport 2Traffic flow forwarding port 2, such as GE 1/0/1vlan id 2VLAN ID carried in traffic flow on Port 2 in theEthernet frame formatBandwidthBandwidth limitation for traffic flow.1UpstreamMaximum bandwidth of upstream traffic flowMaximum(received at port 1, and sent from port 2)Bandwidth.2DownstreamMaximum bandwidth of downstream traffic flowMaximum(received at port 2, and sent from port 1)BandwidthQoSQoS parameter requirement for traffic flowParameter.1Delay.2Delay Jitter.3Packet LossRatio
The traffic flow is forwarded by the DRE based on the VLAN switching table. The process in which the DRE forwards the traffic flow data according to the VLAN switching table is implemented as follows.
When an Ethernet frame of vlan id 1 received at port 1 is sent to port 2, vlan id 1 is swapped into vlan id 2. When an Ethernet frame of vlan id 2 received at port 2 is sent to port 1, vlan id 2 is swapped into vlan id 1.
Through the above forwarding, a VLAN virtual channel may be set up in the network. The virtual channel may be described as: (equipment 1, port 1, vlan id 1)-(equipment 1, port 2, vlan id 2)-(equipment 2, port 3, vlan id 2)-(equipment 2, port 1, vlan id 3) . . . .
The conventional Ethernet switch can only support the transparent transmission of 4096 VLAN tags globally. The V-Switch technology implements the switching between different VLAN IDs and localizes the VLAN ID, so that the VLAN ID has a local meaning.
Although the method for implementing the switching between different VLAN IDs according to a current V-Switch technology can alleviate the problem of insufficient VLAN tag resources, the problem of insufficient VLAN tag resources cannot be solved completely. The number of VLAN tags on each local link is still limited to 4096, and the number of V-Switch connections carried on each local link cannot be larger than 4096. Therefore, the application scale of V-Switch technology is limited.